'use strict';
var single_element = function(collection){
    let temp=[];
    let result=[];
    for(let i=1;i<collection.length;i+=2)
    {
        temp.push(collection[i]);
    }
    for(let i=0;i<temp.length;i++)
        {
            let sum=0;
            for(let j=0;j<temp.length;j++)
                {
                    if(temp[i]==temp[j])
                        sum+=1;
                }
            if(sum==1)
                result.push(temp[i])
        }
    return result;
};
module.exports = single_element;
